Phelps and Tillotson, Jr. — Malonio Acid. 245 



The alcohol used was the alcohol of commerce made as free 

 as possible from water by repeated distillations over fresh cal- 

 cium oxide. Pure zinc chloride of commerce was freshly 

 fused and treated with a current of dry hydrochloric acid gas 

 until a clear melt was obtained ; then this mass was heated for 

 a short time to expel any hydrochloric acid gas before cooling 

 and granulating. 



In every experiment recorded in Table I, weighed portions 

 of malonic acid were treated with definite amounts of absolute 

 alcohol, alone, or charged with a known amount of dry hydro- 

 chloric acid gas with or without a definite weight of zinc 

 chloride, in the special arrangement of flasks described in a 

 former paper for use in esterifying succinic* acid. In all 

 experiments, except those in which the treatment was special, 

 definite amounts of malonic acid with 40 cm3 of absolute alcohol, 

 alone or charged with dry hydrochloric acid gas, or in presence 

 of whatever other catalyzer was employed, were heated in a 

 500 cm3 round-bottomed flask, while the remainder of the alco- 

 hol used containing hydrochloric acid or not, as shown in the 

 table, was boiled in a second 500 cm3 round-bottomed flask, and 

 passed in vapor form to the bottom of the malonic acid solu- 

 tion in the first flask, which was kept at a temperature of 100° 

 to 110° by heating in a bath of sulphuric acid and potassium 

 sulphate. The temperature in the esterification flask was regis- 

 tered by a thermometer dipping into the alcoholic solution and 

 held in place by a three-bored rubber stopper which carried 

 the inlet tube, and also a Hempel bead column, arranged as 

 described in the paper to which reference has been made, to 

 provide an outlet for the vapors liberated in the flask. 



The product obtained was transferred, with the aid of a 

 small amount of ether, to a separating funnel containing 

 chipped ice, and treated with an excess of an aqueous solution 

 of sodium carbonate. The ethereal solution was washed with 

 a solution containing sodium chloride. To recover traces of 

 ester in the wash waters, the carbonate and chloride solutions 

 were shaken out twice, successively, with fresh portions of 

 ether, the ether extracts combined in a 250 cm3 side-necked 

 flask fitted for vacuum distillation, with a capillary tube and 

 receiver consisting of a 100 cm3 side-necked flask connected 

 through a manometer to an aspirating pump. The low-boiling 

 products, consisting chiefly of ether, alcohol and water, were 

 removed by heating the flask containing the ester solution in a 

 water bath, finally at a temperature of 60° for fifteen minutes 

 after the manometer showed a pressure of 15 mm . The water 

 bath was then replaced by an acid potassium sulphate bath, 

 heated to about 140°, and the diethyl malonic ester distilled 



* This Journal, xxiv, 194. 



